Remote control of alternating current (a.c.) power flow through various circuits is a well known application of wireless or "carrier current" technology. Numerous major manufacturers make devices which have a master control which is usually provided as a pushbutton switch that activates a transmitter circuit which emits a uniquely keyed radio frequency signal (or in some cases, an infrared light pulse or ultrasonic signal) that may be received by a remote slave device. The slave device ordinarily is in the form of an adapter which regulates power flow to a remotely controlled load, such as a lamp. The unique character of the wireless control signal is that it may turn the controlled load on and off at the whim of an operator utilizing the master control device.
Leviton Manufacturing Co., Inc. (Little Neck, N.Y.) produces a line of DECORA[.TM.] Electronic powerline coupled carrier current controls which includes the model 6319 controller and the model 6320 transmitter that function as manually operable units which send signals to a variety of remote receiver devices including the model 6381 and 6291 switch modules and model 6227, 6280, 6295 and 6296 receptacle modules. These various devices interactively cooperate to produce remote control of a variety of selectable power circuits, such as lamps, in response to operator instruction uniquely entered into the transmitter module control switch arrangement. PA1 Radio Shack Division, Tandy Corp. (Ft. Worth, Tex.) provides several forms of remote control switch devices, including a model 61-2667 Wireless RF Remote Control Switch that includes a plug-in lamp controller and a hand-held, battery operated remote control that includes two pushbuttons which may serve to remotely turn the lamp controller on or off at considerable distance. Technology of this controller is based upon a Motorola application specific integrated circuit (ASIC) family, typically including the MC145026 encoder and MC145027 decoder thereby providing secure and reliable digital signal sequence based operation. PA1 Stanley Works Inc. (Hartford, Conn.) makes a line of LIGHTMAKER[.TM.] home control units that includes a model 370-2749 or 370-2551 Home Control transmitter unit and a model 370-2475 Wall Switch Module that together enable remote control of a remote electric power load, such as a lamp. PA1 X-10 (U.S.A.) Inc. (Northvale, N.J.) produces a line of POWERHOUSE[.TM.] modules including a model MC-460 transmitter and model LM-465 lamp module receiver. When a touchswitch is pressed on the transmitter a carrier current signal is sent to the receiver module that turns an attached load (such as a lamp) on and off in immediate response to a uniquely coded signal (from a possible combination of 256 different codes) produced by the transmitter that is keyed by the selected touch switch.
A common thread through all of these prior devices is the necessity for an operator to enter a control command into a transmitter, usually as a pushbutton switch action which then initiates a uniquely coded wireless signal (albeit sometimes "carrier current" coupled) that transmits to any remote receivers in the system, with the result that any compatible receiver having a predetermined matching code sensitivity will respond and turn an associated power load on or off.
I have realized that in certain residential settings it might be, for example, more convenient to merely "turn-on" a usual switch which may be integral with or part of an existing "principal" table lamp or other such "load" which then might remotely and automatically turn on one or more separately located "loads", such as other table lamps located elsewhere in a room or even a television receiver or other such device. In this setting, it is preferable that operation of the wireless transmitter/receiver connection is essentially transparent to the user. I have found that sensing change in the state of power flow through a primary power circuit such as that served by the mentioned manually switched principal table lamp may produce a signal that is conditioned to develop a uniquely coded transmitter pulse that serves to activate any number or remote control receiver units that have been preset to respond to the transmitter code signal, all without any special effort on the part of the user aside from the customary act of merely turning the usual switch built into the table lamp on or off.
I have furthermore envisioned my resulting invention as preferably embodied as a module that may plug into a wall receptacle and includes a socket that accepts a plug associated with the operator switched load, such as the mentioned principal table lamp. When the principal table lamp is turned on the state change brought about by the increased current flow produces a usually brief coded carrier current signal that activates one or more suitably preturned receiver modules that may correspondingly turn on other lamps, etc. Conversely, when the table lamp is turned off the resulting state change caused by cessation of current flow briefly produces a differently coded carrier current signal that serves to deactivate each of the one or more responsively pretuned receiver modules, thereby subsequently turning off the other lamps. It is noteworthy that no special user command action is necessary to enable the remote receivers other than the mere turn-on or turn-off of the principal table lamp through utilizing its usual switch. It shall also be understood that "inverse" operation is also taught, that being where the operating mode is such that when the principal table lamp is turned-on, the remote lamp or other load may be automatically turned-off.